The present invention relates to devices useful in testing and adjusting audio sound detecting devices such as burglar alarms or intrusion detectors which are actuated by the sound waves of a particular occurrence and are unaffected by other sounds.
Typically, audio detecting devices are utilized in burglar alarms and intrusion detection devices to detect, audible indications of intrusion, inter alia, breaking glass.
In the prior art the installation of the device and setting the operating parameters for operation of the installed device has been a problem. More particularly the setting of the sensitivity and frequency band of the device has generally been accomplished by trial and error methods. For example, in one method particles of glass are shaken in a container to simulate the sound generated by breaking glass to set the detection limits of the device. In another, and better but more troublesome method, glass is actually broken in the vicinity of the detector to set the limits of operation.
The latter methods have obvious disadvantages and are in fact, of little practical usefulness since it has been found that setting the limits of a sound discriminating detector by utilizing facilities other than sound patterns simulating the actual occurrences prevents full utilization of the capabilities of the sound discriminating device. Further, intrusion into a given location can generate sound frequencies which vary with the method used to accomplish the intrusion.
In a co-pending application Ser. No. 376,170, Durand, now U.S. Pat. No. 4,552,022, one device for selecting the sensitivity of a sound discriminating alarm is disclosed to generate sound of the intrusion in order to fully calibrate audio actuated devices. Additionally, co-pending application Ser. No. 381,955, Durand, now abandoned, describes a method and apparatus for generating simulated audio frequencies.
No other prior art method is known to artifically simulate the audio frequencies and the time change of the amplitude thereof which would normally occur during an intrusion.